Cloud formation and subsequent moisture precipitation



Nov. 5, 1968 Filed March 26, 1965 J. F. BLACK 3,409,220

CLOUD FORMATION AND SUBSEQUENT MOISTURE PRECIPITATION 5 Sheets-Sheet 1FIG. l

LINES OF CONSTANT TEMPERATURE ADVANTAGE FOR ASPHALT LENGTH OF ASPHALTSTRIP, MILES LENGTH OF ASPHALT STRIP, MILES ///4 IBF IO 5 2 0. l W 2 3 45 STABILITY, cm x I07 I I l I L0. 0.5 V 0 0.5 LAPSE RATE, :/|00 METERSFIG. 2

LINES 0F CONSTANT THERMAL MOUNTAIN IIEIeIIT 2s 2o /4000 FEET I5 2000FEET /v 7 /ZIOO0 FEET Io I 5 M 0 4 8 I2 I6 20 WIND SPEED, MILES/HR.

JAMES E BLACK Inventor Patent Attorney J. F. BLACK FIG. 3

CLOUD FORMATION AND SUBSEQUENT MOISTURE PRECIPITATION Filed March 26,1965 I 5 Sheets-Sheet. 2

LINES OF CONSTANT MIXING LENGTH g 40 2' xaz FEET E w 30 i 20 E IO eooFEET l o l0 I5 TEMPERATURE ADVANTAGE FOR ASPHALT, F

FIG. 4

5 g 4.0 3.0 2 z 2o" WATE 2 E f fso" WZTE\R\ LL] 0 20 4o so so I20 I40ASPHALT COATING, MILES JAMES F. BLACK Inventor Patent Attorney Nov. 5,1968 J. F. BLACK 3,409,220

CLOUD FORMATION AND SUBSEQUBNT MOISTURE PRECIPITATION Filed March 25,1965 a Shets-Sheet 3 JAMES F. BLACK Inventor Patent Aflprney nowabandoned.

,arid areas. v

A serious ,problemffacing the-,worldtodayis the lack .ofprecipitationin. large areas. of the world.v Thelack of fprecipitationis partlyithe result of the lack ofproper movement of. air..masses-.having a moisture 1 content.

Un wd S a e Pate? 7 i Q .3,4'09',220' CLOUD FORMATION AND SUBSEQUENT f IM E C P TA' IQN; l I 'James F. BlackaCouvent', N.J.; assignorto'EssoResear'ch and Engineering Company, a corporation of DelawareContinuation-impart of applications Ser; No. 129,107, Aug. 2',1965,--and S er.'N0.r233,377, Oct-3.26,: .1965.

This'application Mal-.26, 1965, Ser. Noi.443,059

, 'rhiea i iiefniefl Sis -aminearioiihlpanldr" no. 129,107 filedflAug.3,],1961, which was abandoned .Nov. 2, 1962, and Ser. 140-233,? filed onOch 26, 1962, and

, The presentinvention is a modifyingilweather. over land. masses- Inparticular, the .instant invention. is. directed toga method of causingatherr al temperature gradient which will effect a. cloud. formationwith a subsequent precipitation of moisture from. such formation. .Thisinventionhas special application -to the situations where moisture-ladenairlcan :be moved over lland-areaswhich arera ther arid and. near thecoast so .as to form clouds andto-cause precipitation overrnlandMoisture laden air doeamove .over certainfareaefwithout theprecipitation of such moisture and the areas thus be- .come useless foragricultural purposes not due tothe lack of fertile soil but due tothelack of rain. Many such .areas'are relatively near oceans and'otherlarge bodies of .water but, nevertheless, they are highly deficient inrainfalL.

It has now been found that byinducing .updrafts large masses ofmoisture-.ladenair can be raised .to-heights .at which cloud formationand condensation. .will occur; By

:this process rainfall andother forms of precipitation may be increasedover a given area of, land. By the means of the. instant process, itbecomes. possible to rehabilitate or renderarable, large areasof landwhichat present are .relatively worthless waste or marginal grazinglands. Thus,

some of the worlds great desert and arid areas may be rendered.productive by an increase-of preci'pitat ior'i I Accordingto thepresentinvention, the foregoing-prob- 'lems and others which areanalogous,-.may be solved in substantial degree by coating selectedlargeand extensive areas of land, i.e., 'atleast 5. or 10 and, -in somecases, .as

much as 100 square miles, withQa material which is' a .highly eflicientabsorber of solar radiation.='lhe land surfacedo be. coatedmay beupsloping such as'hillsides,

mountain ravines, etc. or it may be fiat. It may be coated continuouslyor discontinuously with radiation absorbing materials which aresubstantially different in absorptive and/or radiating properties fromadjoining areas. In many 'and rocksAsphaltis preferred over mostmaterials .for

reasons of economy,-but other materials can be used.. A

reverse etfect'may be created by using white, -or near .white,reflective materials,- such as powdered gypsum, limestone,-calcined1limeand. the like, to coatextensive areas and-thereby create relativelycooler-areas which may cause downdrafts; These coatingsalso may beemployed'in relation .toneighboringblack'coated areas or -.may be'usedalone in some cases to augment the lateral 3,409,220 Patented Nov. 5,1968 .aslit rises, the rate of cooling being in the general range ofabout C. per meters rise. Clouds form as the wat'er vapor in theaircondenses when theascending air reaches, its dewpoint. Thiscondensation is accompanied by strong release of energy (latent heat ofevaporation), which causes :the air. to. rise even more vigorously andmay cause strong updrafts carrying the resulting cloud top to highaltitudes. In summertime the thunderheads which commonly presage violentrainstorms are com monly understoodto be produced by such mechanism. Bystarting an updraft, .due to. heating air near the ground by radiationand conduction from an extensive black .surface, the air may be pushedvigorously up.to where condensation'starts to form clouds. The energyreleased by the condensation itself then pushesthe cloud more rapidlyvto greater heights.

The moisture-laden air moving inland from a large body of water. can beinduced to precipitate its moisture content, or part of its moisturecontent, by increasing the altitude of the air mass. This can be done byplacing a large body in its path. In this regard it is to be noted thatmountain ranges juxtaposed to seacoasts enjoy a greater rainfall thanextensive plains which abut seacoasts. One can but look to the coastlineof Libya and note that the rainfall is almost nonexistent where theplain abuts the coast. However, in the mountainous region of easternLibya it isnoted that. the rainfall is quite heavy. It has been foundthat though erecting physical structures is highly impractical, the sameeffect can be accomplished by creat ing thermal updrafts. These thermalupdrafts, in effect,

create air movement patterns similar to those over an actual mountainmass. It has now been found that these cause cloud formation andprecipitation of the moisture will depend upon the velocity of the wind,the temperature advantage of the asphalt strip, the temperature profilein the atmosphere, the humidity profile, and the amount of waterto be,deposited upon the land to be made arable.

The invention will be more fully understood by referring to theaccompanying drawings wherein:

FIGURE 1 is a graph comparing the effect of length ,of asphalt,temperature advantage and atmospheric stability in producing a thermalmountain of 2,000 ft. efective height.

.FIGURE 2 is a graph relating the length of the asphalt strip towin'dspeed for certain selected thermal mountain, heights.

. FIGURE 3 is a chart depicting the relationship of length of asphaltstrip to the temperature advantage of asphalt.

.FIGURE 4 is a diagram comparing the amount of asphalt coating in milesto the ratio of acres of land made arable to acres of asphalt.

FIGURE 5 is a .profile view of the situation whereby application of.material having substantially greater absorption properties for solarradiation than the general land area, air mass may be moved upwardlyfrom an adjacent lbod-y ofwater to form clouds with resultingprecipitation, and

FIGURE 6 shows in profile an application to a hilly area adjacent to abody of water, an asphalt coating which, with the aid of the upland areacauses moistureladen air to rise to a sufficient altitude to form cloudsand form precipitation over an inland area.

Referring in more detail to the drawings, in FIGURE 1 there is depicteda graphic representation of the influence of atmospheric stability uponthe asphalt strip length needed to produce a 2,000 ft. thermal mountain.The stability scale is also presented in terms of lapse rate which is amore familiar term in the art. The different curves set forth on thegraph are based upon the temperature advantage of the asphalt in F. Itis known that the temperature advantage for asphalt may be as great as27. However, only very readily obtainable temperature advantages are setforth, that is, 9, 12, 15 and 18 F. In making the calculations for thegraph, wind speed was deemed to be 12.1 miles/hour and the mixing lengthwas taken as 16.4 ft. The data from the FIGURE 1 show that with only a 9F. advantage, the asphalt coating requirements are not excessive and forlapse rates of the order of 04 C./ 100 meters, if an 18 F. temperatureadvantage can be realized it is to be realized that a 2,000 ft. thermalmountain can be caused even in the presence of a moderate temperatureinversion. Such is, of course, of importance since certain coastal areashave such temperature inversions.

Referring now to FIGURE 2, there is shown the effect of wind speed uponthe length of the asphalt strips. It can readily be seen that the amountof asphalt needed to produce a mountain of a given elevation increasesrapidly with increasing wind speed. The data for FIG- URE 2 involves theconditions of 9 F. asphalt advantage, a stability of 10" cm. (0.4 C./ lm. lapse rate) and a mixing length of 16.4 it. Under the conditions ofthe data for FIGURE 2 it is to be seen that mountains higher than 2,000ft. will require an almost linear increase in asphalt per increase ofmile per hour of wind speed. Mountain heights of less than 2,000 ft.have a very slight slope up to about 5 miles/hour. It is found that amountain height above which asphalt requirements begin to become largewill vary inversely with the temperature advantage, this is, if thetemperature advantage is 18 F. rather than the 9 used in making the datafor FIGURE 2, the curves, rather than 'being 1,000, 2,000, and 8,000,would approach double those values for substantially the same curve.

FIGURE 3 is a comparison of the temperature advantage and mixing lengthof asphalt for the length of the asphalt needed to create a thermalmountain of 2,000 ft. wherein the wind speed is 12.1 miles/hour and thestability is at cmf It has been found that mixing lengths are converselyproportional to the length of the asphalt strip. However, the importanceof the mixing length is reduced when large asphalt strips of more than30 miles in length are employed, that is, the comparison of mixinglength and temperature advantage to length of asphalt strip simplybecomes a direct comparison between temperature and length at about 30miles of asphalt. The temperature advantage of asphalt will generallyrange from about 8 to F. However, differences as great as 27 F. are notuncommon. The size of the asphalt coating is sensitive to changes intemperature advantage at the extremes, that is, when the temperatureadvantage becomes quite large the length of the asphalt strip requiredbecomes smaller and, conversely, a small temperature advantage wouldrequire an inordinately large asphalt coating. The temperature advantageof the asphalt is simply the difference in temperature between theasphalt coating and the surrounding land mass. It is to be noted fromFIGURE 3 that the length of asphalt required for a normal temperatureadvantage of between 10 and 20 F. is not great; in fact, it will vary atmost by only a factor of 2.

FIGURE 4 is a graphic presentation of the ratio of land made arable toacres of asphalt compared with the length of the asphalt coating. Thereare shown two different curves, one curve representing the comparisonwhen the land made arable is required to receive an average 20" of rainper year and the second line depicting the comparison when the land madearable is required to receive an average 30" of rainfall. These curvesare based upon a thermal mountain created by an asphalt strip 19 mileslong over which a wind having speed of 12.1 miles/hour is blowing. Thethermal mountain is created by this asphalt strip having a temperatureadvantage of 9 F. The stability of the atmosphere is taken at 10 cmfThis thermal mountain has the same general profile as the actualmountain of about 2,000 ft. altitude, previously mentioned, in easternLibya. The 30 curve is based upon the amount of land over which 30"/yearof water would be made available by collecting rainfall from an area inwhich the precipitation is at least l5"/year. In the case of the 20"curve this is the amount of usable land as defined by the area overwhich 20 of water would be made available by collecting rainfall fromareas which receive 10"/year or more of rain. The maximum amount ofarable land per acre of asphalt is reached when the length of asphalt isabout 35 miles. Further increases in the length of the asphalt havelittle beneficial effect.

Referring now to FIGURE 5, a situation is shown which applies to landareas having no substantial hills near a seacoast 50. An area 52 may becoated near the water 51 to cause updrafts 53 with cloud formation 54.The normal sea breezes 55 move the clouds landward and condensationcauses rain to fall over area. 56. The distance 50 between the body ofwater 51 and the coated area 52 can vary from several feet to severalmiles. This distance will vary depending upon the distance the area tobe watered lies from the body of water.

As previously noted, the materials presently preferred for the heatabsorbing and radiating coating are the heavy residual petroleum oilsand asphalt. Asphalt and related normally solid or plastic materialsderived from petroleum residues are relatively inexpensive and areespecially preferred. Among the various forms of asphalt, the aqueousemulsions, either acidic or alkaline, are presently preferred forreasons of economy and ease of application. Cutbacks may be used, oremulsified cutbacks. For example, a square mile of surface may be coatedwith a thin layer of emulsion for a cost under $20,000. By applicationof sufficiently large areas of a highly heatabsorbent and radiativecoating to sites which are properly selected, very substantial risingair currents may be created during daylight hours.

In the case of FIG. 5, for example, the coated area should extend for atleast one and preferably, three or more, miles in depth and at least onemile along the coast. It should be within five or ten miles of the coastif possible. Resulting updraft's 53 are then on a sufficiently largescale to cause incipient condensation and formation of rain clouds 54.These clouds are swept inland by the normal landward breezes 55, causingrainfall over area 56.

By calculations based on known data of temperature, moisture content ofair, and heat effects, it can be shown that precipitation over an areasuch as 56 can be increased by as much as 20 inches per year, and theincreased precipitation can be extended over an area up to three timesas large or larger as the coated area 52.

By coating suitably extensive areas of hillsides to create majorupdrafts or chimney effects, substantial masses of moisure-laden air maybe moved inland at relatively small expense compared with the benefits.Hills or upsloping areas are advantageous but even where there are nosubstantial hills nearby, large mass air movements can be produced bycoating suitable areas, provided that landward breezes are available tomove moisure-laden air overlying a body of water towards the area to becoated. An example of an application to an upland area near a body ofwater is shown in FIG. 6.

A rainfall-deficient area 60, FIG. 6, is shown within reasonabledistance of a large body of water 61, and may sion. An updraft 63 fromthe coated area initiates a strong thermal upflow 64 and lifts warmmoist air 65.

As it rises it condenses to clouds 67. These, meanwhile, are normallymoving inland with the seabreezes, and rain .falls inland from thecoated area. The coated area '62 will be located a distance'68 of fromseveral feet to several miles from the body of water 61. The'distance 68will depend upon the distance the area to be watered lies from the bodyof water. The coating material will gradually disintegrate but a goodcoating properly applied will last several years on many soils, in somecases as long as ten years or more. In particular, with stable soil orrock surface conditions, where wind and water do not cause much erosionor soil movement, a single, thin application of such a coating as acidicor basic emulsion of asphalt may last for quite a number of years beforerequiring renewals, as far as its effects on air currents are concerned.

The lifetime and effectiveness of the coating, particularly when itinvolves asphalt or residual petroleum materials, may be substantiallyincreased by incorporating therein materials which preventdeterioration, or which inhibit or destroy the causes of deterioration.Thus herbicides may be incorporated in the coating itself to preventgrowth of vegetation through the coating. The coating may includeantioxidants. In general, materials inimical to all organic life arecontemplated. In some cases coating materials such as certain types ofasphalt material are subject to extensive attack by animal life.Biological poisons or repellents may be added under suitablecircumstances to prevent or reduce attack by insects, including those inthe larva state and, in fact, may be extended to prevent attack bylarger animate life such as birds and animals.

In some circumstances it may be desirable to fense in the area which iscoated to keep out animals, or to reduce or restrict the movement ofdrifting sand and other material which might obscure or obliterate thecoating. An analogous effect can be achieved by establishing a poison orinhibitor zone around the margin of a coated area, for example, tominimize or prevent encroachment of animal or vegetable life into sucharea.

In lieu of actual poisons, which might be unduly destructive of certaintypes of Wild life, there are available various repellent mate-rialswhich may be employed to discourage animal or insect attack.

Where possible, the dark colored coating material will be applied to thehigher ground, preferably above the inversion level, Where an inversionis involved.

In the prior art a technique is well known for precipitating moisturefrom clouds by cloud seeding. The present invention contemplates, inaddition to the coating of large ground areas with black, or relativelyblack, material to produce strong thermal updrafts and facilitate cloudformation, the use of the cloud seeding technique as an auxiliarymeasure when such appears desirable. Finely divided particles to beemployed for cloud seeding may actually be distributed high in the airprior to actual cloud formation, if desired, so that as they slowlydescend and disperse, they may reach the cloud and begin their effectwhen the cloud is in approximately the desired position to producerainfall. The present invention gives a much better control over theplacing of rainfall than simple cloud seeding per se, even when thelatter is effective. By coordinating the timing of the cloud seedingwith rspect to the updraft produced from the black surface and thelateral air mass travel due to wind or due to a combination of wind andupdraft, moisture may be precipitated in substantial quantities and inapproximately the areas most desired.

The cloud seeding materials and procedures are known in the art andcomprise such materials as finely divided silver iodide", solid carbondioxide'fcarbon-black, ice crystals 'and other solid substances capableof promoting condensation of the cloud moisture into raindrops; By thetechnique just described, rain sometimes may be produced in a cloudwhich otherwise would not quite reach the point of incipientprecipitation. Obviously, the employment of a cloud seedingprocedure isuseless if there are no clouds or if there is insuflicient moisture inthe atmosphere to produce precipitation. The methodof causing largeupdrafts to cause cloud formation, as described above, greatly enhancesthe possibility of producing controlled precipitation. The combinationof these ,two techniques gives a flexibilityand opportunity for largescale weather control not previously available.

Obviously, some of the areas within suitable distance of the lands to bewatered may be coated with relatively white or nonradiating materials,such as lime, gypsum, etc., as described above, to augment or modify theair mass effects. However, the strong updrafts arising from areas whichare black to sunlight are normally sufficiently effective and these areordinarily the predominating factor.

The following example is submitted in order to more particularly pointout applicants invention and is not to be construed as a limitation uponthe scope of the invention as set forth in the appended claims.

Example In order to effect precipitation conditions of an air mass ofabout 86 F. and a relative humidity of about it would be necessary tolift the air about 1,500 ft. Thus in order for our process to beeffective, the asphalt coating must provide at least a lift of 1,500 ft.under such conditions. The lift given to an airstream produced by anasphalt coating may be determined by utilizing the following expression:

at -teen where M=the lift given to the air stream U=the velocity of theair flowing over the coated differentially heated surface K=the eddydiffusivity of the air stream S=the stability of the air (differencebetween adiabatic and actual lapse rates) T=the ground temperatureincrease caused by the asphalt coating T =the temperature of the airstream, and

Lithejlength of the coating (in the direction of wind- Even assuming avery conservative estimate for T of 9 F. the lift derived by a coatingof only 10 miles will be 1,200 to 2,600 ft. for value of U=l.7 to 5.0meters per second. K=8 10 to 7X10 cm. /sec. and S=1 l0- to 2.5)(10- cmfThus a coating having the aforesaid dimensions would provide more thanthe adequate lift to cause the moist air to rise and precipitate itsmoisture content or part of its moisture content.

In view of the temperature advantages which would normally be expectedin the arid costal areas wherein the invention may be used to bestadvantage, the temperature advantage of the asphalt will, in allprobability, be 3040 F. and in these cases lifts of as high as 5,000 ft.can be effected with coatings of about 10 miles square. Therefore, sincelifts as high as 5,000 ft. are not necessary in order to effectprecipitation, considerably smaller areas can be coated with asphalt inorder to effect precipitation in semitropical areas or in areas havingdaytime temperatures of above F.

What is claimed is:

1. A method of causing cloud formation and moisture precipitation over arelatively arid land mass which corn,- prises coating an area of landfor a distance of at least several miles in a direction substantiallyparallel to the 7 direction of the prevailing winds and at least onemile in a direction perpendicular to the prevailing winds with amaterial of high absorptivity to solar radiation to cause an updraftsuch as to lift large masses of relatively humid air over said arid landmass wherein said coating is located within at least ten miles of a bodyof water and between said body of water and said arid land mass andwherein said coating is substantially continuous.

2. A method as in claim 1 wherein said coating material consistsessentially of asphalt.

3. A method as in claim 1 wherein the distance of said coating in thedirection substantially parallel with the prevailing winds is a distanceof from 1 to 40 miles.

a References Cited UNITED STATES PATENTS 1,882,377 10/ 1932 Whittelsey479 2,268,320 12/1941 Brandt 239-44 3,036,015 5/1962 Woodward 252311.5

OTHER REFERENCES Sciencevol. 126, JulyDecember 1957, pp. 637-645.Weather Modification and Smog, by M. Nieburger. (Copy is in theScientific Library of The Patent Office.)

EVERETT W. KIRBY, Primary Examiner.

1. A METHOD OF CAUSING CLOUD FORMATIN AND MOISTURE PRECIPITATION OVER ARELATIVELY ARID LAND MASS WHICH COMPRISES COATING AN AREA OF LAND FOR ADISTANCE OF AT LEAST SEVERAL MILES IN A DIRECTION SUBSTANTIALLY PARALLELTO THE DIRECTIN OF THE PREVAILING WINDS AND AT LEAST ONE MILE IN ADIRECTION PERPENDICULAR TO THE PREVAILING WINDS WITH A MATERIAL OF HIGHABSORPTIVITY TO SOLAR RADIATION TO CAUSE AN UPDRAFT SUCH AS TO LIFTLARGE MASSES OF RELATIVELY HUMID AIR OVER SAID ARID LAND MASS WHEREINSAID COATING IS LOCATED WITHIN AT LEAST TEN MILES OF A BODY OF WATER ANDBETWEEN SAID BODY OF WATER AND SAID ARID LAND MASS AND WHEREIN SAIDCOATING IS SUBSTANTIALLY CONTINUOUS.